Framing deck using 6x6 posts supporting pavillion above

In the planning stage for a pavillion over my RV. Pavillion is 24' wide x 34' long with 6x6 posts used to support double 2x12 beams for roof trusses. Half of the pavillion will have a deck (12'x34') of which half will have a room addition (12'x17').
My question is in regards to the deck framing using the 6x6 posts that are also supporting the pavillion roof. I would like to have the beams in the same plane as the joists instead of below and use joists hangers. The front wall will be constructed of 2x6's directly between the 6x6 posts and the two side walls will come directly off of the 6x6 posts. The back wall (centered under the pavillion) will be of 2x6's. Is my best option for the deck framing to use a sandwich beam - 2 2/12's bolted on either side of the 6x6's as shown below? What is the correct way for blocking in between the sandwich beam, as I have to have somewhere to nail my walls down to? Any help would be greatly appreciated!

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Framing deck using 6x6 posts supporting pavillion above

That is a nice little sketch up you have there, but there is a lot more going on here structurally than anyone can give sound advice on here IMO.

I seriously recommend that you run through this with an engineer. With the deck, roof, and proposed room, there are real load issues to be considered for the footing supports under the posts and inner edge of the deck. Depending on where you are, there could also be frost heave issues, or even the legality of burying the 6 x 6's, and building an enclosed room on the structure.

No one wants to pay an engineer, especially for a DIY job, but it is cheaper than being told you have to tear the structure down.

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Framing deck using 6x6 posts supporting pavillion above

Thanks. Actually it will be going through an engineer. It is a requirement of the county for building permit since the lot is along a river and in a flood plain. I am just doing some preliminary pricing and I just want to make sure I am pricing it in the proper way. I do understand that where the walls are there will be additional dead load therefore the Joists directly under the walls will more than likely need a post in the middle as well...pretty much there would be a beam under each wall is what I anticipate. It is just when I model my projects up I like to have a good grasp on all the techniques before hand...as in the proper way to do the sandwich beam. I haven't even addressed the footers yet and yes our footer depth is 36" due to frost heave. I could essentially add additional posts and beams under the deck so the actual deck and room are not using the pavillion posts for main support...may be a better option.

Framing deck using 6x6 posts supporting pavillion above

Raise the whole structure another 5 feet up the posts! Kidding, but seriously, has anyone heard where they are on redrawing the 100 year flood plain maps?

I know when Fran came through NC in 2000 (99?) They never expected the east side of the State to get flooded out like it did. Then they realized it was the extra 5 billion square feet of roof shingles, concrete and asphalt that had been added to the Raleigh-Durham Triangle. Ooops